Four production bugs from a national SSO platform: X.509 parsing, a misdiagnosed 500, a payment clock race, and Chrome's TLS renegotiation asymmetry

<!-- SC_OFF --><div class="md"><p>Solution architect, 17 years in. From March 2026 to July 2026 I was the only hands-on developer on the identity and single-sign-on layer for a Gulf country's national...